The UPnP standard has increased its importance in becoming a standard for home networking. UPnP is designed to be used in private networks. An example of a private network is a Local Area Network (LAN), such as a home network including networked electronics devices, and has no consideration for accessing devices in a home network remotely, e.g., over the Internet or from another home network.
The Simple Service Discovery Protocol (SSDP) forms the foundation of the UPnP standard. One aspect of the SSDP involves a service discovery request. A UPnP Control Point in a UPnP network multicasts requests to check for any online UPnP Devices. Each UPnP Device must listen for such requests, and when it receives such a request, the UPnP Device sends a unicast response back to the requesting UPnP Control Point. On the other hand, a UPnP Device also periodically advertises itself by multicasting its presence. When a UPnP Control Point receives such advertisement, it can consider that the UPnP Device is online and is ready to be used. As the number of Devices/Services increase, the number of advertisements increases.
This periodic multicasting is not scalable for remote access where Device/Service advertisement must travel over a connecting network (e.g., the Internet) between a home network and a Remote Control Point. This is because the bandwidth available for communication through the Internet is typically much less than that available in a home network. Applying existing UPnP SSDP over the Internet results in increasing consumption of limited bandwidth for the SSDP traffic and thus wasting valuable resources, such as the limited Internet connection bandwidth. Moreover, communication latency over the Internet is difficult to control. Long latencies can cause the Control Point to mistakenly treat a remote UPnP Device as offline, and cause errors in applications. There is, therefore, a need for a method and system for remote access to devices, which addresses the above shortcomings.